This invention relates to sensors for detecting changes in chemical or physical parameters, using optical fibres and techniques associated therewith.
Optical fibres consist essentially of a transparent core surrounded by a thin protective cladding. The latter is in the form of a coating of lower refractive index than the core, and light fed into the core is transmitted along the fibre through the core being internally reflected at the core/cladding interface. The cores are usually of silica fibres, but other materials such as organic polymers may also be used, an essential requirement for the core being transparency at the wavelength of the light used.